1. Field of the Invention
This invention relates to a device for polishing floor-surface with a pad, which is rotated at a high speed by a motor, during the traveling operation of the device (this device will be hereinafter referred to as "floor polisher"), and more particularly to a floor-surface polisher equipped with a function for adjusting a pad pressure, in which a constant force for uniformly pressing the pad against floor-surface can be maintained (in other words, the pad can be uniformly intimately contacted with the floor-surface).
2. Brief Description of the Prior Art
A typical conventional floor-surface polisher of the type mentioned above has the problem in that a force for pressing the pad against the floor-surface is changed during operation, due to various causes such as wear of the pad, reduced voltage of the batteries, state of the floor-surface, and the like, and as a result, the quality level of the polishing job for the floor-surface is changed.
In view of the above, the inventor of the present invention has developed floor-surface polishers as discussed in previous Japanese Patent Application No. Sho 62-290363 (Japanese Laid-Open (KOKAI) Patent Application No. Hei 1-131640) and Japanese Utility Model Application No. Hei 2-405014 (Japanese Laid-Open (KOKAI) Utility Model Application No. Hei 4-93054), in which a pad is moved up and down by a motor, so that a force for pressing the pad against the floor-surface can be adjusted to normally maintain a constant level.
However, since the above conventional floor-surface polisher has a complicated mechanism for moving the pad up and down with the power of a motor, the cost becomes high. In addition, it is very difficult to maintain the pad pressure normally at a constant level by a motor. If the pad pressure is too strong, there is a possibility that the wax applied to the floor-surface comes off and the floor-surface applied with wax is scratched. In contrast, if the pad pressure is too weak, a sufficient polishing effect can not be obtained. Therefore, a solution is demanded.
The present invention has been accomplished in view of the above problems inherent in the conventional devices.